The otoliths of a chimaera, the new zealand elephant fish callorhynchus milii

Abstract

The elephant fish Callorhynchus milii (Holocephalidae) has a pair of well‐developed otoliths corresponding (in relative position) to the astericus and sagitta in teleosts. Although the elephant fish apparently lacks a lapillus, there are a well‐developed set of cristae at the base of the semicircular canals. The cristae presumably serve the same balance function as the lapillus. The semicircular canal system also contains a well‐developed ductus endolymphaticus, filled with irregular calcium carbonate otoconia. A different type of oto‐conia are found fused together to form the two otoliths. This latter type of otoconia, a crenellated spherulite, is similar to those found aggregated in the otolith of the lungfish Neoceratodus forsteri, and found as loose otoconia in association with the sagitta in some species of teleosts. © Crown copyright 1987.